Slip rotation apparatus



G. M. NELL Aug. 16, 1932.

INVENTOR. fiz/smve M/VW/ Filed April 6. 1929 SLIP ROTATION APPARATUS ATTORNE Y.

Patented Aug. 16, 1932 earns eus'rAvn'iu. ELL; or nn'rnorr, MICHIGAN,Assrenon r cnfceeo rivnniuarrc TOOL COMPANY, on NEW YORK, 1\T.Y., Aoonronerron or nnwannsnr SLIP ROTATION I APPARATUS Application filedApril 6,

This invention relates to rock drilling machines and tools, withparticular reference to the mechanism by which the drill steel isrotated or stepped around during the drill- :3 ing operation.

lVith conventional rock drills of the self rotating type using rifle barmechanism, the sticking of the drill steel tends to cause the entiremachine to rotate. If the tool is hand Z supported the operator canresist such movement and shut ofl the air. But in the case of the selfrotated stoper the guiding handle is sometimes whipped out of theoperators hand and as the machine rotates it winds up the hose and mayinjure the operator before he can get the machine under control. Thestuck steel must then be loosened and in forcibly rotating or rockingthe machine or in using a bar in the handle or other opening in themachine to secure a leverage, the rotation mechanism is often subjectedto a strain beyond its strength with the result that the rifle barbreaks or the threads holding the rifle nut in place arestripped.

One object of the invention is to prevent damage to drills and injury tooperators when drill steels become stuck. Another object is to providefor release or slipping ofthe rotation mechanism when subjected toexcessive strain. Another object is to devise simple andinexpensivemechanism for securing the above results, which mechanism isreadily adaptable to old as well as new machines. Other objects will beapparent from the detailed description which follows.

The invention involves means for causing a slip in the rotationmechanism, as between the rifle bar nut and the piston, so as tominimize, or entirely to prevent, rotation of the machine, as a Wholewhen the drill steel is under abnormal torsional load or becomes stuck,but which will providefor rotation of the drill steel undernormal'conditions.

. By preference the slip grip or friction in 45 the rotation mechanismis made proportional to the torsional strength of the parts most likelyto break, so that slip will occur before these parts are overloaded orunduly strained. s In order to illustrate the invention one 1929.")Serial no. 353,206.

concrete embodiment'thereof is shown in the accompanying drawing, inwhich:

'Fig. 1 is a fragmentary sectional view of so much of a rock drill as isnecessary for the understanding of the invention;

Fig. 2 is a transverse sectional view throughthe piston shown in Fig. 1substantially on the line 22 of Fig. l and Fig. 3 is a right endelevational view of the piston.

The embodiment of the; invention chosen for, the purpose ofillustration, discloses a portion of a fluid pressure, self-rotatingrock drillhaving a cylinder A in which reciprocates an impact member orpiston 4: arranged todeliver blows as well as to impart rotation to a,drill steel (not shown). The reciprocatory movement of piston 4 isutilized to eflect rotation of the samethrough mechanism of the riflebar type which includes a rifle bar 5 suitably supported in the rear endor back head (not shown) of the drilling machine and extends axially ofthe piston chamber to cooperate with a rifle nut 6 supported in a,recess 4a in the rear end of the piston, which recess has a reduced eX-tension 4?) to receive bar 5. The rotativeimpulse imparted to pistonlistransmitted by ribs or flutes 40 on the latter in sliding engagementwith similar flutes Z) on achuck B into which the drill steel. (notshown) extends. I I

In order to prevent breakage of the parts of the rotation mechanism, orinjury to the operator due to the rotation of the entire machine in theevent ofa stuck steel, a slip connection is provided somewhere in therotation train. By preference this slip connection takes the form of aflexible and automatically detachable coupling which is provided onpiston 1-. To this end nut 6 has a smooth annular exterior which isjournalled in the smooth annular bore of a retainer 7 which takes theform of an externally threaded sleeve for cooperative threadedengagement with the internal threads of recess 4a of piston 4. On itsinner end, retainer 7 has a recess 7 a of greater diameter thanits boreto receive a radial flange Go on nut 6, which flange is clamped againstthe'bottom of recess lawhen 2) of nut 6 While the other end 86 isengaged in a slot 7 Z) in retainer? The rifle nut, retainer, springassembly (6, 7, 8) is inserted as a unit in recess 4a of piston 4, awrench being applied to flats 70 (Fig. 3) on the head of retainer 7. Thescrew threads are in the proper directionto causeretainer 7 to screwinto the piston under the impulse or reaction of the rotation mechanismand to take up any clearance between the flanged head 6a of rifle nut 6andthe bottom of recess a so as to prevent relative longitudinalmovement of nut '6. The intensity of this clamping action is limited bythe amount of rotational impulse transmitted bythe flexible couplingeffected between nut-S and retainer 7 by "spring '8, and it isobvious'that asthe friction between the bottom of recess 4a and flange6a of the nut increases, there will be a decrease in the screwing upimpulse transmitted to retainer 7. Hook end 8a of spring 8 and thecooperating recess 66' in rifle nut 6 are so formed and of such extentas to transmit through coupling spring 8 sulficient impulse for normalrotation requirements but hook end 8a will release or slip out of recess66 when the rotative impulse exceeds a predetermined amount or becomesexcessive through the sticking of the drill steel. 7

I am aware that protection of the rotative mechanism may be securedotherwise than by providing the flexible connection between the riflenut and the piston, and that other forms of slip and friction'alengagingarrangements may be used without departing from the spirit of thisinvention. I therefore do not desire to limit the invention to thespecific form shown but intend to cover all modifications, adaptations,and equivalent combinations within the scope of the appended claims.

I claim as my invention:

1. In a percussive drill, in combination, a reciprocating percussivemember, means responsive to the movement ofsaid member for impartingrot'ative movement to the same,

'" and means on said member responsive to overload for effecting slipbetween said first named means and said member.

QJIn a percussive drillhaving a reciprocating impact member, rifle barmechanism for imparting rotation to said memberineluding a rifle nutcarried by the latter, and means permitting slip between said nut andsaid member "when said mechanism is overloaded.

'3. In a percussive drill having a reciprocluding a rifle nut rotatablymounted upon said member, and means providing a yielding connectionbetween said nut and said memberarranged :to disengage when saidmechanism becomes overloaded.

5. A piston for a percussive drill having a recess at one end, a riflenut, means securing said nut in said recess for rotative movement, andmeans establishing a yielding connection between saidnut and saidpiston.

6. A piston for a. percussive drill having a recess at one end, a riflenut, a retainer securing said nut in said recess, and means establishinga said nut and said piston; I

--i piston for -a percussive drill having a recess at one end, a riflenut, a retainer securing said nut in said recess and providing a bearingtherefor, and a slip connection between said nut and said retainer.

-8. A piston for a percussive drill having a recess at one end, a riflenut having a'flange at one end, a retainer sleeve for securing said nutin said recess with said flange against the bottom thereof, and a slipconnection betweensaidnut and said sleeve.

9. A piston for a percussive drill having a recess atone end, a'riflenut, a retainer securing said nut said recess and providing a bearingtherefor,- and -'a spring establishing. a "slip connection between saidnut and said retainer) r l0. A piston-for a percussive drill havingrecess at one end, a rifle nut having a. flange 'a-t'one end, a retainersleeve 'forse'curing said nut in said recess'with said flange againstthe bottom thereof, and-a spring encircling said flange and arranged toprovide a slip eon nection between said nut and said sleeve. 7

11. A piston for a percussive drill having a recess atone end, a riflenut having-a flange at one end, a retainer sleeve for securing said nutin'sai'd recess with said flange against the bottom thereof, and aspring encircling "said flange and having reversely directed endsengaging said nut and said sleeve respectively to provide a slipconnection between said nut and said sleeve. Y

12; Arifle nut and retainer for insertion as a unitinto a recess in thepiston of a fluid pressure tool,- said nut and retainer being intelescoping engagement and relatively rota-t able, and a flexiblecoupling therebetween arranged to disengage when a predetermined torqueupon either is exerted.

13. Arotative unit for'threaded insertion yielding connection betweeninto a recess in the piston of a fluid pressure tool comprising anexternally threaded sleeve having a smooth central bore, a rifle memberrotatably received Within said bore and k having a radial flangeengaging one end of said sleeve, and a flexible coupling between saidsleeve and said member arranged to disengage when subjected to apredetermined torque. 3

r 14. A rotative unit for threaded insertion into a recess in the pistonof a fluid pressure tool comprising an externally threaded sleevehavinga recess at one end and a reduced axial bore therethrough, a riflemember having a portion journalled in said bore and a radial flangeseated in said sleeve recess, and a spring encircling said flange'Within said sleeve recess and releasably engaging said sleeve andmember to provide a flexible con- V nection therebetween.

15. A retainer for securing a rifle nut in the recessed end of a pistoncomprising an externally threaded sleeve having a smooth axial boretherethrough and a recess at one end of slightly greater diameter thansaid bore to receive a radial flange on the rifle nut.

Signed by me at Detroit, in'the county of Wayne and State of Michigan,this 2nd day 33 ofApril, 1929.

GUSTAVE M. NELL.

